Logic and Change

LAC - 7035

Work Area: Knowledge Engineering and Representation

Keywords logic and change, reasoning about action, temporal reasoning, declarativity

Start Date: 1st October 92 / Duration: 36 months / Status: running

[ participants / contact ]

Abstract LAC focuses on the definition of declarative approaches to handle the phenomena of action and change, which arise in areas like planning, belief revision, concurrent and multiagent systems. The approach is to study the use of specialised logics (linear logic, modal logic, temporal logic) for declarative implementation and reasoning about such phenomena.


Reasoning is an integral part of intelligent systems. In reality any such system has to cope with a changing world. This is certainly true for humans, but also for robots, database management systems, human/computer interfaces, programming environments, etc. Hence reasoning must account for change in order to be truly useful in practice.

Logical approaches to artificial intelligence have the advantage of offering a declarative framework for the representation of knowledge. On the other hand, Classical logic, the generally assumed logical theory in AI, was originally conceived for the static world of mathematics, and is not well equipped to deal with the notions of action and change, which are often crucial in the problems that AI is meant to address. Many of the criticisms against the "logicist" view of AI find one of their main motivations in this inadequacy to deal with change. However, recently the AI community has started to consider alternative logical theories which are better equipped to cope with the problems of change. Among such theories are modal logic, temporal logic, Girard's linear logic and Bibel's linear proofs.

The aim of the project is to bring together researchers looking for a satisfying logical account of change, and to examine ways to mechanise the logic in order to implement systems that perform change and systems that reason about change.


The Group focuses on the joint discussion and analysis of problems and aspects of change as they occur in many application domains, eg planning, concurrent systems, multiagent worlds, non-monotonic reasoning, inheritance with exceptions, change and logic programming, and truth-maintenance. Besides smaller informal meetings, the workplan consists of three internal workshops, mainly aimed at interaction among members, and two open workshops, with a public call for participation, aimed at interaction of the Group with the rest of the research community. Expected results are insights into the nature of change as well as the elaboration of logical frameworks able to provide common views of various aspects of change.

Progress and Results

Progress should be evaluated in terms of gaining a broader and clearer perspective on the theme of the Group than that provided by the many particular and fragmented approaches. With only one internal workshop held during the first year, it is still too early to present meaningful results.


This project can potentially foster the foundation of novel programming paradigms, suitable for a declarative approach to complex computational tasks. These paradigms may lead to the design and implementation of concrete programming languages and environments whose declarativity can have a big impact on the reliability and production cost of large software systems.

Latest Publications

Information Dissemination Activies

The first open workshop of the Group will be held in conjunction with ECAI-94 in Amsterdam, the major European forum for Artificial Intelligence research and therefore a good opportunity for information dissemination.


Instituto de Desenvolvimento de Novas Tecnologias
Quinta da Torre


Technische Universität München - D
Universität Karlsruhe - D
Université de Paris XIII - F
Università di Roma La Sapienza - I
Università di Torino - I
Linkoping University - S
Imperial College of Science, Technology and Medicine - UK


Prof. A.B.G. Porto
tel +351/1 295 3270
fax +351/1 295 5641

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LAC - 7035, August 1994

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html version of synopsis by Nick Cook